ML16161A935
| ML16161A935 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 12/23/1987 |
| From: | Bryant J, Peebles T, Skinner P, Wert L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML16161A933 | List: |
| References | |
| 50-269-87-49, 50-270-87-49, 50-287-87-49, NUDOCS 8801110415 | |
| Download: ML16161A935 (5) | |
See also: IR 05000269/1987049
Text
.
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UNITED STATES
o)
NUCLEAR REGULATORY COMMISSION
REGION II
-<
101 MARIETTA STREET, N.W.
ATLANTA,GEORGIA 30323
Report Nos.:
50-269/87-49, 50-270/87-49, and 50-287/87-49
Licensee:
Duke Power Company
422 South Church Street
Charlotte, NC 28242
Docket Nos.: 50-269, 50-270,
License Nos.: DPR-38, DPR-47, and
and 50-287
Facility Name:
Oconee 1, 2, and 3
Inspection Conducted: N vember 20 -
December 7, 1987
Inspectors:
Approved by: ____________,__________________
2
T. A. Peebles, Section ChiefDteSgd
r an
ate/Signed
H.
kinnDate
S igned
Division of Reactor Projects
SUMMARY
Scope:
This special,
unannounced inspection involved resident inspector
inspection in the area of containment integrity during refueling operations.
Results:
In the area inspected, one violation was identified.
9t801110415 971229
FPtR
ADOCK 05000269
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REPORT DETAILS
1.
Licensee Employees Contacted:
- M. S. Tuckman, Station Manager
R. L. Sweigart, Operations Superintendent
C. L. Harlin, Compliance Engineer
- F. E. Owens, Assistant Engineer, Compliance
Other licensee employees contacted included technicians, mechanics and
staff engineers.
Resident Inspectors
- J. C. Bryant
P. H. Skinner
L. D. Wert
- Attended exit interview.
2. Exit Interview
The inspection scope and findings were summarized on December 7, 1987,
with those persons indicated in paragraph 1 above.
The licensee did not
identify as proprietary any of the materials provided to or reviewed by
the inspectors during this inspection.
The following new item was
identified:
Violation
269,270,287/87-49-01:
Failure
to
Maintain
Containment Integrity During Refueling Operations.
3.
Licensee Action on Previous Enforcement Matters
Not inspected.
4.
Unresolved Items
Not inspected.
5.
Loss of Containment Integrity During Refueling Operations
On October 12,
1987, during reinsertion of fuel into the Unit 1 reactor,
the licensee notified the resident inspectors that air inleakage had been
detected at the containment emergency hatch through, installed temporary
seals.
Refueling operations had been stopped until the situation was
corrected. An investigation of the event was begun by the licensee and
findings of the investigation are provided in detail in Licensee Event
Report 50-269/87-08 which was issued November 25, 1987.
2
Oconee Nuclear Station (ONS)
Technical Specification (TS)
3.8.6 requires
that during the handling of irradiated fuel in the reactor building, at
least one door on the personnel and emergency hatches shall be closed.
The purpose of TS 3.8.6 is to prevent spread of contamination outside
containment in the event an irradiated fuel element is dropped during
handling.
At times,
due to ongoing work being performed in containment during
outages, it is necessary to have both of the emergency air lock hatches
open in order to permit piping and electrical connections from temporary
equipment
outside containment to
equipment being
serviced inside
containment, to pass through the hatches.
Examples of work requiring
this adjustment are sludge lance
and water slap cleaning of steam
generators and,
during the recent Unit 1 outage, chemical cleaning of
the steam generators.
Due to outage time considerations,
it
is very
beneficial to provide temporary sealing of the emergency lock hatches
to avoid extension of the refueling outage by several weeks.
During
refueling, TS Interpretation 3.8 permits sealing the emergency hatch to
prevent airflow by methods other than having one hatch closed, when it is
necessary to permit ongoing work to continue.
Description of Physical Layout
The emergency lock is 5 feet in diameter and 12 1/2 feet long overall.
Ith a hatchway 2 1/2 feet in diameter toward each end of the lock.
Both hatches open inward toward containment. Both hatches are operated
by a common shaft which is geared to provide sequential opening and
closing. The shaft is so geared that it is impossible to have one hatch
open unless the other is closed. Also, as the locking dogs are released
when either hatch is opened, an equalizing valve is cammed open to relieve
differential pressure.
When
it
is necessary to
have both hatches open while maintaining
containment isolation during refueling operations,
it
is necessary to
,physically disconnect the operating -
interlocking mechanism.
A steel
closure plate is then installed inside the lock to replace the inner
hatch.
The closure plate
has penetrations with welded-in
protruding toward containment.
Necessary piping and cables are passed
through the sleeves. The sleeves are then sealed from inside the airlock
with a tough sealant foam to make the penetrations air tight.
Problems Experienced With Hatch Sealing
During the Unit 1 EOC 10 refueling outage, several things went wrong with
the job control process which resulted in defeating the sealing of the
emergency hatch. Also, the licensee's investigation determined that the
hatch probably had not been properly sealed on three earlier refueling
3
outages when temporary seals were used on emergency hatches, since the
procedure did not require sealing the 1" diameter equalization lines.
The events, as identified by the licensee, were as described below:
a.
The temporary modification designer did not realize that when the
emergency hatches were opened equalization valves were cammed open.
With both doors open,
equalization valve outlets would need to be
sealed to avoid providing a path from containment
to outside
atmosphere. There was no provision in the plan for sealing these
openings. The designer had used portions of a previous job plan in
preparing his job plan.
That job plan did not require sealing the
equalizing line. This led the licensee to suspect that the previous
temporary modifications might have failed to seal the line also.
b. After all items had been installed-through the closure plate, foaming
of the plate was assigned to a Construction and Maintenance Division
(CMD) crew. The Planning and Scheduling Coordinator (P&SC) informed
the CMD supervisor that the work should be done under a specific job
plan, and furnished an incorrect job plan number. The supervisor was
not informed that the work was safety related and, therefore,
a
procedure was required and a procedure was available for the work.
c.
The CMD lead man who was to perform the work was not sure of the
proper place to install the foam.
He made several phone calls to
CMD and ONS management but those he contacted could not answer his
questions. He was then advised by the P&SC,
who provided somewhat
ambiguous directions. The lead man then had the work performed by
building two dams about six inches apart inside the outer hatch of
the emergency lock, then foaming between the dams.
The work was
completed on September 22, 1987.
d.
On September 24, ONS Operations signed off a refueling procedure step
which verified that the temporary door had been installed in the
emergency hatch; defueling of the reactor began and was completed on
September 28. Sealing of containment was not required again until
October 10 when refueling began.
e.
On October 12 at 1:30 p.m. the reactor building coordinator (RBC) was
informed that air was coming through the closure plate and light
could be observed through the opening. The RBC verified the air flow
but did not notify Outage and Operations management until about
3:10 p.m. Fuel movement was then secured until the seal had been
repaired.
The licensee's investigation also determined that the
equalization valve was not sealed. This also was corrected.
Discussions With Personnel Involved
In the inspectors' discussions with the modification designer, who was on
emergency leave when the seals were installed, the P&SC and the CMD lead
man who performed the job, it became evident that there was considerable
lack of understanding and confusion between the principals. In the past,
4
the sleeves had been foamed from inside the airlock throuch the inner
hatch toward the inside of the containment building.
To do this, the
workmen had to crawl through the 30 inch diameter outer hatch and around
the cables and piping passing through it.
The designer recognized that during this particular outage with the
addition of two large pipes for chemical cleaning, it would be impossible
for the workmen to crawl through the outer opening to reach the inner
hatch. His intent was that the foaming be done into the sleeves from
inside the containment building. He had taken pictures of the seal plate
with sleeves and labeled them as taken from inside the reactor building
to indicate how the foam should be introduced. He was not aware that CMD
preferred to avoid taking the foam machine into a contaminated area.
The
P&SC was
aware that the
foam machine would not be taken into
containment, but was not aware that, with the additional piping, workers
could not enter the air lock from the yard area in order to foam in the
same manner as in the past.
The CMD
lead man believed he should not take the foam machine inside
containment, was told to foam from the outside, and did it
in the only
manner he saw possible.
Reaching into the lock through the outer hatch,
he constructed two
forms
around the cables
and
pipes
and
foamed
inbetween.
The work was done with the general foaming procedure,
but
without the work package and procedure on hand;
however,
the general
procedure was of little value for this particular job.
Results of Loss of Containment Integrity
There was no release of activity to -the environment .
A purge normally
is maintained during refueling activities, which maintains a slight
negative pressure in containment.
Also, there wa.s no dropped fuel or
other occurrence which released unusual activity during any of the four
periods mentioned when integrity was not maintained.
LER 50-269/87-08
,describes the FSAR analysis of fuel handling accidents.
This analysis
shows that had a fuel
handling accident occurred at the time,
the
consequences would be bounded by the analysis and that doses at the site
boundary would have remained below the limits of 10 CFR 100.
This is
Violation
269,270,287/87-49-01:
Failure
to -Maintain
Containment
Integrity During Refueling Operations.